I have a 20hp Briggs Intek engine that leaks at the shaft oil seal. I replaced it an seated the seal down to the inner shoulder, because that's where the old seal was. It began leaking again. I looked around on the internet and saw that the seal should not be seated that deep, so I replaced it again. This time I seated just below flush. I ran the engine a bit over the weekend, but noticed it leaking again last night. There is an oil re-circulation hole below the inner shoulder, so the seal was not interfering with that in either situation. Does anyone know what may be going on? I saw a product by Blue Devil that is supposed to fix leaky seals. Has anyone tried it? Thanks for any advice!